CBS News projects Texas Republican Sen. Ted Cruz will be re-elected to a second term in the Senate, fending off a strong challenge by Rep. Beto O'Rourke, a rising star in Democratic politics.

Exit polls indicated Texas voters were relatively split about what they think the most important problem is facing the country. Over a third of voters said health care was the most important problem. Two-thirds of those voters went for O'Rourke.

Of the third of voters who believe that immigration is the most important problem, about three-quarters supported Cruz. Almost a quarter of voters thinks the economy is the country's biggest problem, and among them, the majority voted for Cruz.

Twenty-two percent of voters in Texas were voting in a midterm for the very first time. These voters leaned towards O'Rourke by 7 points, while return voters favored Cruz by 6 points.

College graduates split their votes evenly between the two Senate candidates, while those without a degree voted for Cruz 53 to 46 percent.

White evangelicals favored Cruz with 83 percent of their votes, while those not in this group supported O'Rourke by a nearly 2-to-1 margin.

Cruz emerged on the national political scene in 2012 as a Tea Party star. He orchestrated a government shutdown in 2013 and was the runner-up for the Republican nomination in the 2016 presidential election. However, while he gained national attention, these high-profile actions may have backfired back home.

Enter Beto O'Rourke, a charismatic El Paso-area congressman with an ability to attract a large and passionate following -- and an extremely large campaign war chest. O'Rourke, who has visited every county in Texas during his campaign, raised more than $38 million in the final quarter before the election, an unprecedented amount for a Senate race. O'Rourke and his followers believed that a progressive congressman could win the hearts of voters in deep-red Texas, but their effort fell short.

Although Cruz led O'Rourke in the polls, the fact that the race was so close concerned national Republicans and excited Democrats. National Democrats have dreamed of a blue Texas for years, thanks to changing demographics and increased urbanization.

Follow the Texas Senate race news and live election results below:

Some polling hours were extended

Polls closed at 7 p.m. Central Time (8 p.m. ET) across most of Texas. Portions of west Texas closed at 7 p.m. Mountain Time (9 p.m. ET).

A judge ordered nine polling places in Harris County to remain open one hour later. Harris County, which includes most of the Houston metro area, is a Democratic stronghold and also the home turf of Ted Cruz.

O'Rourke posted a video on Twitter urging voters to stick it out. "If you are in line to vote, stay in line, even if it's after 7 o'clock," he said. "As long as you're in line you'll be able to get to the front of that line, ultimately, and cast your ballot."

As the various congressional districts tally and report to the Texas secretary of state, CBS News has live election results for all races across the Lone Star State.

Texas Senate candidates

Beto O'Rourke (D)

A 46-year-old El Paso, Texas, native, Robert "Beto" O'Rourke entered the national political stage in 2012 after defeating the incumbent Democratic Representative Silvestre Reyes and winning a seat in Congress, campaigning on a platform that included LBGT rights and liberalization of drug laws.

As a congressman, O'Rourke supported increased accountability for the Customs and Border Protection agency, including the establishment of protocols to report deaths and use of force at the U.S.'s southern border. His Senate campaign has ignited grassroots passions among liberals who've long been outnumbered at the voting booth in deep-red Texas.

Prior to entering politics, O'Rourke co-founded Stanton Street Technology, a internet services and software company. He served as a city councilman in El Paso from 2005 to 2011, following in his father's footsteps.

O'Rourke attended Columbia University in New York, where earned a B.A. in English literature and played in a punk rock band that toured the U.S. and Canada during summer breaks. He is married to Amy Hoover Sanders and father of three.

Ted Cruz (R)

Sen. Ted Cruz, 47, become involved in national politics in 1999 as a domestic policy advisor on the George W. Bush presidential campaign. He worked on Bush's legal fight over the 2000 Florida presidential recount and served as associate deputy attorney general in the U.S. Department of Justice.

Cruz returned to Texas in 2003 to serve as solicitor general, then went into private law practice. He won his Senate seat in 2012 after defeating the GOP lieutenant governor in a primary that the Washington Post called "the biggest upset" that year. His fervent conservative views made him a polarizing figure. Cruz lost a bitterly fought race for the 2016 GOP presidential nomination to Donald Trump, but they overcame that history to campaign together at a rally last month.

Cruz received a B.A. in public policy from Princeton University's Woodrow Wilson School of Public and International Affairs and went on to earn his J.D. from Harvard Law School. He married Bush economic advisor and Goldman Sachs investment manager Heidi Nelson Cruz in 2001; the couple has two children.

Immigration in the spotlight in Texas Senate race

What to watch for

Do Democrats turn out?

It wouldn't be enough for O'Rourke to turn out all the Democrats who usually vote in midterm elections. He'll need to mobilize voters who generally don't turn out in large numbers in off-year elections. This includes minority communities, young people, unaffiliated voters and moderate Republicans.

Early voting totals are an indication that this election year will be different than previous midterms, which have historically low turnout. Early voting in Texas has already surpassed the total vote in the entire 2014 midterms.

Are Latinos mobilized?

Democrats see Latinos as the key to taking red states on the Southern border, such as Texas and Arizona. O'Rourke speaks Spanish fluently, and often does interviews with Spanish-language channels, such as Univision. He has also made immigration a focal point of his campaign.

Two Democratic Latina candidates are likely to become the first Latinas to represent the state in Congress. But these factors do not guarantee that Latino voters turn out, or that they will vote for Democrats. Cruz could appeal to more socially conservative and evangelical Latinos.

Is there a measurable Trump effect?

President Trump visited Texas in October to stump for Cruz at a rally with tens of thousands of attendees. The president has been rallying non-stop in the final weeks before the election, in an attempt to convince his base voters that the election is a referendum on his presidency, even if he isn't on the ballot.